overlays: i2c-sensor: Add the jc42 class of sensor

This is a second attempt to solve issue 5234, since it turns out that
the mcp980x driver only supports MCP9800-MCP9803. MCP9804, MCP9805 and
MCP9808 require the jc42 driver.

See: https://github.com/raspberrypi/linux/issues/5234



Signed-off-by: Phil Elwell <phil@raspberrypi.com>